When I was born, the world's population was 3.5 billion. There are now 6.8 billion people on the planet. By 2050, that's expected to rise to 9.4 billion. What's more, the Earth's resources aren't growing; they're decreasing - and rapidly.
I've been on swims where people have freaked out about sharks. You have to think about something else, otherwise it will absolutely paralyze you. I do math problems, anything.
The problem with climate change is that it's quite complicated for the ordinary person to understand.
On 15 July 2007, I swam across an open patch of sea at the North Pole to highlight the melting of the Arctic sea ice.
I learned two basic lessons on Everest. First, just because something has worked in the past does not mean it will work today. Second, different challenges require different mindsets.
The days of exploration of Shackleton and Scott are long gone. Everything has been climbed, crossed, done. Now what we're exploring are the full boundaries of human endeavour. It's not physical - it's all in the head.
